The former chief executive of Kenya's indebted Nakumatt Supermarkets will be investigated over the loss of 18 billion shillings ($179 million) worth of stock, an administrator for the retailer said on Thursday.

Nakumatt went into voluntary supervision earlier this year after seeking protection from its creditors.

Nakumatt, which grew from a mattress shop in a rural town to have branches across Kenya and East Africa, was forced to shut more than a dozen outlets last year as it struggled to repay its suppliers, landlords and other creditors.

Peter Kahi, Nakumatt's court-appointed administrator, said he would seek a forensic investigator to investigate why Atul Shah, its former chief executive, wrote off stock worth 18 billion shillings in May, before the company ground to a halt.

Sought protection using Kenya's new company laws

"I don't think it is something which happened within a year or a day. Maybe it is a build-up of so many years. Because 18 billion is quite a big sum, just to occur in one day," he told Reuters by phone.

"Of course that is a big write-off, which according to them (the company) it's basically pilferage, shrinkages and theft by staff and what ... But now it is for him to explain, since he was the chief executive officer."

Shah declined to comment and referred Reuters to Kahi when contacted for comment.

When it sought protection in October, Nakumatt had 4,000 staff, but it has closed several outlets since then.

The company sought protection using Kenya’s newly enacted company laws, which provide a pathway for distressed firms to avoid complete collapse.